1. Field of the Invention
The present invention relates to telecommunication systems especially wireless systems, wireless transmitters and wireless receivers, especially those using the Bluetooth standard. The present invention also relates to semiconductor integrated circuits that implement a wireless receiver and/or a wireless transmitter especially those using the Bluetooth standard, as well as software for implementing the transmitter and/or receiver.
2. Technical Background
The Bluetooth wireless interface, introduced by the Bluetooth Special Interest Group (Ericsson, Nokia, IBM, Toshiba and Intel) in 1998, is designed to be a low-cost, low-power and short-range cable replacement.
Version 2.0+EDR of the Bluetooth standards introduces an Enhanced Data Rate (EDR) operation. The EDR standard is an improvement over the Basic Rate standard. New modulation schemes: π/4-DQPSK and 8DPSK, are proposed as well as the conventional GFSK. The bandwidth of the channel is 1 MHz.
The unit establishing a connection is called a master. The master unit uses a free-running clock to periodically transmit in every second slot and poll/select one of the slaves in a piconet by implicitly assigning the next slot for the transmission. There are two types of links:                synchronous connection oriented (SCO)        asynchronous connection-less (ACL)        
One of the distortion problems that needs to be compensated in a system using Bluetooth EDR is the system clock drift. Normally there can be a maximum clock drift of 40 ppm between two devices. The effect of clock drift is that gradually the best sampling point drifts away from the one selected during correlation in the receiver. This can result in some bit errors at the end of the packet for long packets in 3 Mbps EDR (3-DH5 packets).